Me: “Yes you do. Remember, you failed miserably in heavy traffic on U.S. 26.”

Siri: “Searching for directions on U.S. 26.”

Me: “OK. Play dumb. But a year ago, I wrote about how drivers should steer clear of using you and other voice-activated apps to send text messages in traffic. In fact, I concluded that relying on you was nearly as distracting as using my hands. Here’s the video. (I searched for it on my own.)”

More recent evidence, focusing on texting, has made similar conclusions. In one study published last year, a team of researchers at the Virginia Tech Transportation Institute evaluated the performance of drivers texting on a closed road. Some texted from their handheld device, which previous research had already concluded was dangerous, while others texted through an in-vehicle system connected to Bluetooth.No surprise that drivers who texted by hand drove very poorly: they reported greater mental demand during the drive, took longer glances away from the roadway, and steered worse compared to baseline driving performance. Those who used the in-vehicle system did a little better. They didn't have much problem receiving text messages through the in-car system, but sending them posed a problem.Even sending a voice text as simple as "I'm stuck in traffic" led drivers in the study to glance off the road more often and longer than usual, and they too reported a higher mental demand during this part of the test.

There’s even a graphic demonstrating the “mental demand.” And this isn't the only study coming to these conclusions."